As a conventional example of a technology for joining a roof arch extending in a vehicle transverse direction to a roof side rail extending in a vehicle body front-rear direction, a technology described in Patent Literature 1 can be taken. In Patent Document 1, described is a technology for joining a roof arch (roof bow) to a roof side rail by mounting the roof arch from an upper side for a purpose of improving the attaching work of the roof arch.
Further, as conventional examples of technologies for joining a pillar extending in the upper-lower direction together with a roof arch to a roof side rail, technologies described in Patent Literatures 2 and 3 can be taken. In Patent Literature 2, described is a technology for joining a roof arch (roof rail) and respective inner members (side inner members), which are a pillar and a roof side rail, through a gusset. This gusset is provided with an anti-drop portion and an anti-deviation portion, by which positioning in attaching or assembling is made easy and the gusset is prevented from dropping.
In Patent Literature 3, described is a technology for forming click portions at the front and rear end portions of a gusset and forming beads between these paired click portions. According to this technology, opening portions for stopping the click portions are offset in the front-rear direction, and the load transmission efficiency is improved by the beads. Further, a technology is described for preventing a pillar garnish from moving off in expanding a side curtain air bag, by engaging a stop convex portion at the upper end of a pillar garnish to a bead.